WebBrowser Event Handling Question

[chief7]

I am using the following code to intercept a link click event in a webbrowser control:

    Private Sub wb1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles wb1.DocumentCompleted
        wb1.Document.Links(0).AttachEventHandler("onclick", AddressOf LinkClick)
    End Sub

    Sub LinkClick(ByVal sender As Object, ByVal e As System.EventArgs)
        MsgBox("link was clicked; ")
    End Sub

This works, but I want to be able to stop the browser from following the link. How can this be accomplished?

 

[JohnH]

This onclick event happens before Webbrowser Navigate event which may be cancelled.

[SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff]Private [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] WebBrowser1_DocumentCompleted([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], _
[/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) _
[/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2] WebBrowser1.DocumentCompleted
 WebBrowser1.Document.Links(0).AttachEventHandler([/SIZE][SIZE=2][COLOR=#800000]"onclick"[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]AddressOf[/COLOR][/SIZE][SIZE=2] LinkClick)
[/SIZE][SIZE=2][COLOR=#0000ff]End [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff] 
[/COLOR][/SIZE][SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] LinkClick([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.EventArgs)
 bCancel = [/SIZE][SIZE=2][COLOR=#0000ff]True
[/COLOR][/SIZE][SIZE=2] MsgBox([/SIZE][SIZE=2][COLOR=#800000]"link was clicked, navigation cancelled."[/COLOR][/SIZE][SIZE=2])
[/SIZE][SIZE=2][COLOR=#0000ff]End [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff] 
[/COLOR][/SIZE][SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] bCancel [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff] 
[/COLOR][/SIZE][SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff]Private [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] WebBrowser1_Navigating([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], _
[/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Windows.Forms.WebBrowserNavigatingEventArgs) _
[/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2] WebBrowser1.Navigating
[/SIZE][SIZE=2][COLOR=#0000ff] If[/COLOR][/SIZE][SIZE=2] bCancel = [/SIZE][SIZE=2][COLOR=#0000ff]True [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Then
[/COLOR][/SIZE][SIZE=2]  e.Cancel = [/SIZE][SIZE=2][COLOR=#0000ff]True
[/COLOR][/SIZE][SIZE=2]  bCancel = [/SIZE][SIZE=2][COLOR=#0000ff]False
[/COLOR][/SIZE][SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff] End [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]If
[/COLOR][/SIZE][SIZE=2][/SIZE][SIZE=2][COLOR=#0000ff]End [/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub
[/COLOR][/SIZE]

 

[chief7]

thats cool.

can you evaluate what the css class or the link text of the link was?

 

[JohnH]

Not from this event. Otherwise get the text of the link from the innerText property. Use GetAttribute to get some attribute, the class attribute is special so you have to ask for className instead.

MsgBox(WebBrowser1.Document.Links(0).GetAttribute("className"))
MsgBox(WebBrowser1.Document.Links(0).innerText)

 

[chief7]

Let me explain what I am trying to do. I have what is similar to an online textbook written in vb6, where you read some text and can click "shortcut links" to open new vb windows. I am currently using a rich text box for the text and am parsing the click event for the "shortcut links".

Now I want to convert the app to .net and have a windows and web based app. I assumed that replacing the rtb with html would work better for both. The goal is to have only one set of text that can be used for both apps. Is this a valid idea? Is there a better way to do this?

 

[JohnH]

Yes, I agree with that, create regular webpages with the content to display in any web browser, online or local.

 

[pitaridis]

Link problem

How can I find which link has been clicked?

 

[JohnH]

That is not possible to find out from the link click.